The Vatican hasn’t yet released an official itinerary for Pope Francis’ September trip to Washington, D.C., New York and Philadelphia, but that hasn’t stopped the news from being released by other sources.

Enough of the major elements of the journey have been announced by other parties that we are beginning to get a good idea of what’s coming and when.

First, it’s important to remember that the reason Pope Francis is making the journey in the first place is to be present at the World Meeting of Families in Philadelphia, which begins Sept. 22. For Catholics, at least, this will be the pinnacle of his trip, and it will be the place where the pope will celebrate a public Mass, which is expected to draw up to 2 million people.

But the rest will be thrilling to follow, as well. So let’s start piecing it together.

Pope Francis likely will arrive in Washington, D.C., on the evening of Sept. 22. One of his first stops, confirmed in a statement released by the White House at the end of March, will be the White House on Sept. 23 for an official welcoming ceremony. During this visit, the statement said, President Barack Obama and Pope Francis “will continue the dialogue ... on their shared values and commitments on a wide range of issues.” Also while in D.C., perhaps even that afternoon, Pope Francis will canonize Blessed Junipero Serra at the Basilica of the National Shrine of the Immaculate Conception, an event the pope confirmed himself in January. There is likely to be a Mass associated with the canonization, but most likely not open to the public. UPDATED April 20: The Vatican confirmed that the canonization will take place Sept. 23 at 4:30 p.m. on the lawn of the Basilica of the National Shrine of the Immaculate Conception.

Thanks to a February announcement by House Speaker John Boehner, we also know that Pope Francis will address a joint session of Congress while in the nation’s capital — the first pontiff to do this — on Sept. 24.

“In a time of global upheaval, the Holy Father’s message of compassion and human dignity has moved people of all faiths and backgrounds,” Boehner said. “His teachings, prayers, and very example bring us back to the blessings of simple things and our obligations to one another.”

Francis will then head north to New York City, where the United Nations has announced that he will address the U.N. General Assembly on the morning of Sept. 25.

Francis is then expected in Philadelphia on Sept. 26-27 to conclude the World Meeting of Families. Events will include a Saturday evening prayer vigil and a Sunday Mass, which will be open to the public.

Many gaps in this tentative outline remain, particularly in New York. And of course a major question is what role Pope Francis’ well-known penchant for spontaneity will play. I think it’s safe to say we should all be ready to expect the unexpected.

No matter what happens, it’s sure to be a grace-filled week, and one that will make a long-lasting impact on the American Church.